Field of the Invention
The present invention generally relates to surgical fasteners, and more specifically relates to curved surgical fasteners for securing prosthetic devices such as surgical mesh to tissue.
Description of the Related Art
Hernia is a condition whereby a small loop of bowel or intestine protrudes through a weak place or defect within the abdominal muscle wall or groin of a patient. This condition commonly occurs in humans, particularly males. Hernias may result from a congenital defect whereby the patient is born with this problem, or may be caused by straining or lifting heavy objects. Heavy lifting has been found to create a large amount of stress upon the abdominal wall, which can cause a rupture or tearing at a weak point of the abdominal muscle to create the defect or opening. In any Hernia case, a patient may be left with an unsightly bulge of intestinal tissue protruding through the defect, which may result in pain, reduced lifting abilities, and in some cases, impaction of the bowel, or possibly other complications if the flow of blood is cut off to the protruding tissue.
A common solution for correcting a hernia condition is surgery. During a surgical procedure, the defect is accessed and carefully examined, either through an open incision or endoscopically through an access port such as a trocar. In either case, careful examination is required due to the network of vessels and nerves that exist in the area of a typical defect, which requires a surgeon to conduct a hernia repair with great skill and caution. Within this area can be found vascular structures such as gastric vessels, the external iliac vessels, and the inferior epigastric vessels, as well as reproductive vessels such as the vas deferens extending through the inguinal floor.
Once the surgeon is familiar with the anatomy of a patient, the surgeon carefully places the viscera back into the patient's abdomen through the defect. Repairing the defect can involve closure of the defect with sutures or fasteners but generally involves placing a surgical prosthetic such as a mesh patch over the open defect, and attaching the mesh patch to the abdominal wall or inguinal floor using sutures or surgical fasteners. The mesh patch acts as a barrier and prevents expulsion of bowel through the defect.
Inguinal hernia repair involves the placement and fixation of a surgical mesh over a defect. There are specific sites that must be avoided due to the presence of blood vessels and nerves (known as the triangle of doom and triangle of pain), and specific sites that can be used for mesh fixation (Cooper's ligament, Lacunar ligament, abdominal wall). The Cooper's ligament, also known as the Pectineal ligament, lies on the superior pubic ramus of the pelvis. The thickness of this ligament is typically 1 mm to 3 mm.
Suture is the standard for hernia mesh fixation and is used for affixing mesh to the Cooper's ligament. Suturing of the mesh patch to the inguinal floor can be well suited to open procedures. In laparoscopic procedures, however, suturing is not preferred due to the greater skill and time required.
Adhesives have also been used for hernia mesh fixation, including fibrin and cyanoacrylate adhesives. The use of adhesives has been limited, however, due to high cost, special storage conditions, preparation, and diminished effectiveness on wet tissue.
Self-adhering surgical mesh is also used for laparoscopic hernia repair. Some surgeons have noted some difficulty in handling due to self-adhesion. In addition, surgeons often prefer the additional security of mechanical fixation of the mesh to tissue.
Surgical fasteners are often used during endoscopic or open procedures for attaching mesh patches to the inguinal floor. One of the earliest types of endoscopic procedures involves the use of a surgical stapler that dispenses staples into tissue. The surgical stapler typically has a stack of unformed staples that are contained within a stapling cartridge in a serial fashion. The staples are sequentially advanced or fed within an applicator instrument by a spring mechanism. As the staples are dispensed, an anvil engages the arms of the staple to bend the arms into a closed, clamping position.
Another hernia mesh attachment instrument uses a helical wire fastener that resembles a small section of spring. Multiple helical wire fasteners may be stored serially within a shaft of an applicator instrument, and may be corkscrewed or rotated into tissue. A load spring may be used to bias or feed the plurality of helical fasteners distally within the shaft.
Surgical fasteners have generally been made of metal, such as stainless steel, nitinol, or titanium. The use of metal fasteners was necessary to provide for sufficient holding strength, penetration of various prosthetic meshes, and for ease of manufacture. Although metallic mesh fixation devices are very effective at securing mesh to the Cooper's ligament, it is suspected that metallic devices contribute to long-term patient pain and discomfort.
In response to problems associated with using permanent, metal fasteners, absorbable mesh fixation devices have been developed for securing mesh to tissue. Until recently, there were no absorbable tissue fasteners available on the market, and surgeons could only use absorbable sutures in order to provide a fixation means that did not permanently stay in the body. However, using sutures is exceedingly difficult for laparoscopic procedure, and so they are generally not used unless the repair is done in an open fashion. With surgical trends leading to more minimally invasive techniques with minimum foreign body accumulation, there remains a need for absorbable tissue fasteners for affixing mesh to tissue that can be applied laparoscopically, whereby the tissue fastener has a minimum profile.
Thus, in spite of the above advances, there remains a need for further improvements in surgical fasteners. In particular, there remains a need for surgical fasteners having a minimum profile, surgical fasteners having smaller profiles, surgical fasteners that achieve sufficient anchoring force in tissue, surgical fasteners that may be applied laparoscopically, surgical fasteners that have superior holding strength, surgical fasteners that will not injure vessels and nerves, and surgical fasteners that are absorbable.